Recently, in the medical field, methods of using a balance arm (hereinafter also called a support arm) having an imaging device provided on the front edge of the arm to carry out various medical procedures such as surgeries while observing an image of the surgical site captured by the imaging device have been proposed. By using a balance arm, the affected area may be observed consistently from a desired direction, making it possible to carry out medical procedures efficiently.
On the other hand, when observing a surgical site with an imaging device, there is demand to be able to observe the surgical site from different distances and different angles, while keeping the viewpoint locked onto the surgical site. To address such demand, technology that causes the imaging device to perform a tilting movement centered on a point on the optical axis, referred to as a pivot operation, is being developed. With a pivot operation, an operation is realized in which the imaging device is kept pointed at a certain point in three-dimensional space (the pivot center point), and the imaging device is made to move over the surface of a cone whose apex lies at the certain point. For example, Patent Literature 1 discloses a medical equipment support apparatus (balance arm) that realizes a pivot operation of an imaging device by appropriately joining together multiple link mechanisms with a coupling mechanism that couples with these link mechanisms.